EFI FAST IDLE VALVE HEATER NEW 'FIV' HEATER P/N

VEHICLES AFFECTED: 1975-1980 DeVille, Brougham, Eldorado and Seville

A fast idle on 1975-1980 Cadillacs equipped with Electronic Fuel Injection (EFI) that does not decrease as the engine warms up may be caused by the Fast Idle Valve (FIV) heater.

A new FIV heater has been released for service on all 1975 through 1980 EFI equipped vehicles. This new FIV heater is currently available from GMYDD in limited quantities, as P/N 1628898, and can be identified by an epoxy heat transfer compound surrounding the wax motor rather than the silicone heat transfer compound (white paste) used in the old style-valve

Diagnose the Fast Idle Valve heater system as follows:

1. Inspect entire throttle linkage for proper operation.

2. Inspect engine vacuum hoses for:

A. Leake or breaks

B. Improper routing

C. Disconnected

3. Adjust engine curb idle speed and ignition timing to the appropriate specification on the vehicle emission label.

4. Using a voltmeter, check for voltage to the FIV heater at the engine harness terminals of the FIV connector. Voltage should be the same as battery voltage.

The FIV is powered the same as the electric fuel pumps and will only be powered for approximately one second when ignition switch is turned 'on', unless the engine is running or being cranked.

5. Remove all Fast Idle Valve components from the throttle body assembly Service Manual for procedures), and visually inspect the plastic valve and seat for rough surfaces which could cause sticking or binding during component operation. Also, inspect electrical terminals for corrosion or contamination, since an improper electrical connection will also cause improper operation. Correct as require.

Note: The Fast Idle Valve contains a latch spring. If the FIV heater encounters an overheat condition, the spring will latch the vlave and orifice in a closed position. Do not remove the latch spring.

6. If steps 1-5 do not identify a cause of a fast idle, replace Fast Idle Valve heater with P/N 1628898.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.